What happens when the source of light rays is a mirror?

In summary: This is because the camera is positioned to receive all the rays from a single point on the object [the mirror], and so they are all focused onto the same point on the film.
  • #1
Brian99
3
0
As far as I understand, the film inside a photo camera is positioned in such a way that every light ray that hits some spot X on the film comes from a single source on the object being photographed. Here's what I mean:

http://static.howstuffworks.com/gif/camera-diagram3.gif

The various light rays from the top of the pencil, no matter where or at what angle they hit the lens, will be focused to one point on the film.

If so, then I have two questions:

1. What about interference effects between the rays of light? Since they all hit the same point on the film, and come from the same source, it seems they will be coherent and should produce interferene at that point.
Yet we don't see that when taking photographs.

2. What about when the source of the rays is not an object (pencil, etc.) but a mirror? In that case, even if the rays come from the same point on the mirror, they are still of different colors (frequencies) since they are reflections of light rays entering the mirror. And yet, all these various frequencies from the same point in the mirror will hit one single spot on the film. Shouldn't this produce a mix of colors on the resulting photograph, instead of a picture of reflection that we expect?

Thanks - Brian
 
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  • #2
1. Each ray has a different optical path length, so they will not arive at the lens or image at the same time. Thus there will not be any interference.

2. Everything we see is a superpostion of all frequencys present. This should not be remarkable.
 
  • #3
Integral said:
1. Each ray has a different optical path length, so they will not arive at the lens or image at the same time. Thus there will not be any interference.

The rays that will arrive at the image at the same time will be coherent (since they are coming from the same source), thus there should be interference.

2. Everything we see is a superpostion of all frequencys present. This should not be remarkable.

Re-read my post above ...The following image shows the situation I have in mind: http://i2.tinypic.com/wsql2r.jpg

The green and blue rays are reflected off a mirror, at the same point, and then enter the lens and are focused onto a single point A [this will happen for every ray coming from the same point on the mirror]. As a result, any photodector/film/etc. on point A should detect a mix of all colors [from rays coming from all angles], yet in reality we only see one color from one ray.
 

What is the relationship between mirrors and light?

The relationship between mirrors and light is that mirrors reflect light. When light hits a mirror, it bounces off the reflective surface at the same angle it came in at, creating a reflection. This reflection allows us to see objects in front of the mirror.

How are mirrors able to produce an image?

Mirrors are able to produce an image through a phenomenon called specular reflection. This means that the angle of incidence (the angle at which light hits the mirror) is equal to the angle of reflection (the angle at which light bounces off the mirror). This creates an image that appears to be behind the mirror, but in reality, the light is reflecting off the mirror's surface.

How does a camera use mirrors and light to take photos?

A camera uses mirrors and light to take photos by using a combination of lenses and mirrors to focus and reflect light onto a photosensitive surface (such as film or a digital sensor). The light passes through the lens, which bends and focuses the light onto the mirror, and then onto the photosensitive surface, creating an image.

Why do some mirrors make objects appear smaller or larger?

Some mirrors make objects appear smaller or larger due to the curvature of the mirror's surface. A convex mirror (curved outwards) will produce a smaller image, while a concave mirror (curved inwards) will produce a larger image. This is due to the way the light is reflected and how it interacts with the mirror's surface.

How does the angle of incidence affect the reflection of light off a mirror?

The angle of incidence directly affects the reflection of light off a mirror. The angle of incidence is the angle at which the light hits the mirror, and the angle of reflection is the angle at which the light bounces off the mirror. The law of reflection states that the angle of incidence is equal to the angle of reflection, meaning that the light will bounce off the mirror at the same angle it came in at.

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